JP7288806B2 - Water heater - Google Patents

Description

The technology disclosed in this specification relates to a water heater.

Patent Document 1 discloses a heat pump heat source that heats water, a tank that stores water heated by the heat pump heat source, a circulation path that connects the heat pump heat source and the tank, a circulation pump provided in the circulation path, A water heater is disclosed that is connected to a tank and includes a hot water outlet passage for supplying water stored in the tank to a hot water supply location, and a control device. The control device includes a hot water supply operation for supplying water stored in a tank to a hot water supply location, a boiling operation for driving a circulation pump and a heat pump heat source, and storing water heated to a boiling target temperature in a tank, and a circulation anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent the water in the passage from freezing.

JP-A-2003-139405

In the water heater of Patent Document 1, water is heated by a heat pump heat source during anti-freezing operation. The water heated in the anti-freezing operation is supplied to the circulation path and also stored in the tank. That is, heat is stored in the tank as a result of the anti-freezing operation.

In general, antifreeze operation minimizes the energy used to heat the water. Therefore, the temperature of the water stored in the tank during the anti-freezing operation is relatively low and lower than the temperature of water suitable for hot water supply (hereinafter referred to as "hot water supply temperature"). Therefore, when the hot water supply operation is performed after the antifreeze operation is performed, the water stored in the tank must be reheated to the hot water supply temperature. In order to avoid such a situation, a technology is conceivable in which the energy used for heating water in the anti-freezing operation is increased to raise the temperature of the water stored in the tank to the temperature of the hot water supply. However, heat is radiated from the tank during the time from the end of the anti-freezing operation to the start of the next hot water supply operation (hereinafter referred to as "standby time"). Therefore, when the standby time is long, even if the water in the tank is heated to the hot water supply temperature in the anti-freezing operation, most of the heat stored in the tank is dissipated. Therefore, the heat dissipation of the heat stored in the tank is suppressed in the anti-freezing operation, and the heat stored in the tank is effectively used in the anti-freezing operation, so that the water at the desired hot water supply temperature is discharged as much as possible. There is a demand for a technique that can rapidly perform

The present invention suppresses the heat dissipation of the heat stored in the tank during the anti-freezing operation, and effectively utilizes the heat stored in the tank during the anti-freezing operation, thereby making it possible to supply hot water at a desired temperature. To provide a technique that can be carried out as quickly as possible.

The water heater disclosed in this specification includes a heat pump heat source that heats water, a tank that stores water heated by the heat pump heat source, a circulation path that connects the heat pump heat source and the tank, and the circulation path. a circulation pump provided in the tank; a hot water outlet passage connected to the tank for supplying water stored in the tank to a hot water supply location; and a control device, wherein the control device is connected to the tank a hot water supply operation in which the stored water is supplied to the hot water supply location; a boiling-up operation in which the circulation pump and the heat pump heat source are driven to store water heated to a boiling-up target temperature in the tank; an anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent the water inside from freezing; In the anti-freezing operation, the control device sets the time from the anti-freezing start time, which is the time at which the anti-freezing operation is started, to the scheduled hot water supply start time. is longer than the specified time, the circulation pump and the heat pump heat source are driven to perform a low-temperature anti-freezing operation in which the water in the circulation path is heated to a low-temperature anti-freezing temperature, and the hot water supply is performed from the anti-freezing start time. When the time until the scheduled start time is less than the first specific time, the circulation pump and the heat pump heat source are driven to raise the water in the circulation path to a high temperature anti-freezing temperature higher than the low temperature anti-freezing temperature. A high-temperature anti-freezing operation for heating is executed, the high-temperature anti-freezing temperature is the boiling-up target temperature, and the control device performs the boiling-up operation a second specific time before the scheduled hot water supply start time. The second specific time is a time different from the first specific time and is the time required for the boiling operation.

As described above, heat is radiated from the tank during the standby time. The longer the standby time, the greater the heat dissipation from the tank. Also, the higher the temperature of the water in the tank, the greater the heat radiation from the tank. According to the above configuration, the control device executes the low temperature antifreeze operation when the time from the antifreeze start time to the scheduled hot water supply start time is equal to or longer than the first specific time. If the time from the freeze prevention start time to the scheduled hot water supply start time is longer than or equal to the first specific time, the standby time is relatively long. In this case, most of the heat stored in the tank during the low-temperature anti-freezing operation is dissipated during the standby time. The temperature of the water in the tank after the low temperature antifreeze operation is lower than the temperature of the water in the tank after the high temperature antifreeze operation. Therefore, compared with the case where the high-temperature anti-freezing operation is executed when the time from the anti-freezing start time to the scheduled hot water supply start time is equal to or longer than the first specific time, heat radiation from the tank during the standby time can be suppressed. can be done.

Also, when the waiting time is short, the heat dissipation from the tank is small. According to the above configuration, the control device executes the high-temperature anti-freezing operation when the time from the anti-freezing start time to the scheduled hot water supply start time is less than the first specific time. Much of the heat stored in the tank during the high temperature antifreeze operation can be utilized in subsequent hot water supply operations. The temperature of the water in the tank after the high-temperature anti-freezing operation is higher than the temperature of the water in the tank after the low-temperature anti-freezing operation, and the temperature of the water is more suitable for use in the hot water supply operation. Therefore, in addition to implementing the anti-freezing operation, the heat stored in the tank during the anti-freezing operation is also used as the heat for the hot water supply operation, making it possible to supply hot water at the desired hot water temperature. can be done as quickly as possible.

Another water heater disclosed by this specification includes a heat pump heat source that heats water, a tank that stores water heated by the heat pump heat source, a circulation path that connects the heat pump heat source and the tank, and a circulation pump provided in a circulation path; a hot water discharge path connected to the tank for supplying water stored in the tank to a hot water supply location; and a control device, wherein the control device a hot water supply operation for supplying water stored in a tank to the hot water supply location; a boiling operation for driving the circulation pump and the heat pump heat source to store water heated to a boiling target temperature in the tank; anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent water in the circulation path from freezing, and the control device starts the next hot water supply operation. A scheduled hot water supply start time, which is a scheduled time, can be obtained. If it is longer than or equal to the first specific time, the circulation pump and the heat pump heat source are driven, the low-temperature anti-freezing operation is performed to heat the water in the circulation path to the low-temperature anti-freezing temperature, and the anti-freezing start time is reached. When the time until the scheduled hot water supply start time is less than the first specific time, the circulation pump and the heat pump heat source are driven to prevent water in the circulation path from reaching a temperature higher than the low temperature antifreeze temperature. A high temperature anti-freezing operation is performed to heat up to a temperature, and the water heater further includes an outside air temperature sensor for detecting outside air temperature, the lower the outside air temperature, the shorter the first specific time.

As described above, heat is radiated from the tank during the standby time. The longer the standby time, the greater the heat dissipation from the tank. Also, the higher the temperature of the water in the tank, the greater the heat radiation from the tank. According to the above configuration, the control device executes the low temperature antifreeze operation when the time from the antifreeze start time to the scheduled hot water supply start time is equal to or longer than the first specific time. If the time from the freeze prevention start time to the scheduled hot water supply start time is longer than or equal to the first specific time, the standby time is relatively long. In this case, most of the heat stored in the tank during the low-temperature anti-freezing operation is dissipated during the standby time. The temperature of the water in the tank after the low temperature antifreeze operation is lower than the temperature of the water in the tank after the high temperature antifreeze operation. Therefore, compared with the case where the high-temperature anti-freezing operation is executed when the time from the anti-freezing start time to the scheduled hot water supply start time is equal to or longer than the first specific time, heat radiation from the tank during the standby time can be suppressed. can be done.
Also, when the waiting time is short, the heat dissipation from the tank is small. According to the above configuration, the control device executes the high-temperature anti-freezing operation when the time from the anti-freezing start time to the scheduled hot water supply start time is less than the first specific time. Much of the heat stored in the tank during the high temperature antifreeze operation can be utilized in subsequent hot water supply operations. The temperature of the water in the tank after the high-temperature anti-freezing operation is higher than the temperature of the water in the tank after the low-temperature anti-freezing operation, and the temperature of the water is more suitable for use in the hot water supply operation. Therefore, in addition to implementing the anti-freezing operation, the heat stored in the tank during the anti-freezing operation is also used as the heat for the hot water supply operation, making it possible to supply hot water at the desired hot water temperature. can be done as quickly as possible. Even if the standby time is the same, the lower the outside temperature, the greater the heat radiation from the tank. Therefore, in order to suppress the heat dissipation during the standby time when the outside temperature is low to the same extent as the heat dissipation during the standby time when the outside temperature is high, the standby time when the outside temperature is low should be reduced to the standby time when the outside temperature is high. It should be shorter than the time. According to the above configuration, the lower the outside air temperature is, the shorter the first specific time is. Therefore, heat radiation from the tank can be suppressed, and the heat stored in the tank can be effectively used in the anti-freezing operation, so that water at a desired hot water supply temperature can be supplied as quickly as possible.
Even if the standby time is the same, the lower the outside temperature, the greater the heat radiation from the tank. Therefore, in order to suppress the heat dissipation during the standby time when the outside temperature is low to the same extent as the heat dissipation during the standby time when the outside temperature is high, the standby time when the outside temperature is low should be reduced to the standby time when the outside temperature is high. It should be shorter than the time. According to the above configuration, the lower the outside air temperature is, the shorter the first specific time is. Therefore, heat radiation from the tank can be suppressed, and the heat stored in the tank can be effectively used in the anti-freezing operation, so that water at a desired hot water supply temperature can be supplied as quickly as possible.

Another water heater disclosed by this specification includes a heat pump heat source that heats water, a tank that stores water heated by the heat pump heat source, a circulation path that connects the heat pump heat source and the tank, and a circulation pump provided in a circulation path; a hot water discharge path connected to the tank for supplying water stored in the tank to a hot water supply location; and a control device, wherein the control device a hot water supply operation for supplying water stored in a tank to the hot water supply location; a boiling operation for driving the circulation pump and the heat pump heat source to store water heated to a boiling target temperature in the tank; anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent water in the circulation path from freezing, and the control device starts the next hot water supply operation. A scheduled hot water supply start time, which is a scheduled time, can be obtained. If it is longer than or equal to the first specific time, the circulation pump and the heat pump heat source are driven, the low-temperature anti-freezing operation is performed to heat the water in the circulation path to the low-temperature anti-freezing temperature, and the anti-freezing start time is reached. When the time until the scheduled hot water supply start time is less than the first specific time, the circulation pump and the heat pump heat source are driven to prevent water in the circulation path from reaching a temperature higher than the low temperature antifreeze temperature. A high-temperature anti-freezing operation is performed to heat up to a temperature, and the higher the high-temperature anti-freezing temperature, the shorter the first specific time.

As described above, heat is radiated from the tank during the standby time. The longer the standby time, the greater the heat dissipation from the tank. Also, the higher the temperature of the water in the tank, the greater the heat radiation from the tank. According to the above configuration, the control device executes the low temperature antifreeze operation when the time from the antifreeze start time to the scheduled hot water supply start time is equal to or longer than the first specific time. If the time from the freeze prevention start time to the scheduled hot water supply start time is longer than or equal to the first specific time, the standby time is relatively long. In this case, most of the heat stored in the tank during the low-temperature anti-freezing operation is dissipated during the standby time. The temperature of the water in the tank after the low temperature antifreeze operation is lower than the temperature of the water in the tank after the high temperature antifreeze operation. Therefore, compared with the case where the high-temperature anti-freezing operation is executed when the time from the anti-freezing start time to the scheduled hot water supply start time is equal to or longer than the first specific time, heat radiation from the tank during the standby time can be suppressed. can be done.
Also, when the waiting time is short, the heat dissipation from the tank is small. According to the above configuration, the control device executes the high-temperature anti-freezing operation when the time from the anti-freezing start time to the scheduled hot water supply start time is less than the first specific time. Much of the heat stored in the tank during the high temperature antifreeze operation can be utilized in subsequent hot water supply operations. The temperature of the water in the tank after the high-temperature anti-freezing operation is higher than the temperature of the water in the tank after the low-temperature anti-freezing operation, and the temperature of the water is more suitable for use in the hot water supply operation. Therefore, in addition to implementing the anti-freezing operation, the heat stored in the tank during the anti-freezing operation is also used as the heat for the hot water supply operation, making it possible to supply hot water at the desired hot water temperature. can be done as quickly as possible. Even if the standby time is the same, the lower the outside temperature, the greater the heat radiation from the tank. Therefore, in order to suppress the heat dissipation during the standby time when the outside temperature is low to the same extent as the heat dissipation during the standby time when the outside temperature is high, the standby time when the outside temperature is low should be reduced to the standby time when the outside temperature is high. It should be shorter than the time. According to the above configuration, the lower the outside air temperature is, the shorter the first specific time is. Therefore, heat radiation from the tank can be suppressed, and the heat stored in the tank can be effectively used in the anti-freezing operation, so that water at a desired hot water supply temperature can be supplied as quickly as possible.
Even if the standby time is the same, the higher the temperature of the water in the tank, the greater the heat radiation from the tank. For this reason, in order to suppress heat dissipation during the standby time when the water temperature in the tank is high to the same extent as heat dissipation during the standby time when the water temperature in the tank is low, the water temperature in the tank must be high. It is necessary to make the waiting time shorter than the waiting time when the temperature of the water in the tank is low. According to the above configuration, the higher the high-temperature anti-freezing temperature (that is, the temperature of the water in the tank after the high-temperature anti-freezing operation), the shorter the first specific time. Therefore, heat radiation from the tank can be suppressed, and the heat stored in the tank can be effectively used in the anti-freezing operation, so that water at a desired hot water supply temperature can be supplied as quickly as possible.

The control device can acquire the scheduled hot water supply start time based on the history of past hot water supply to the hot water supply location, and performs the boiling-up operation a second specific time before the scheduled hot water supply start time. may be configured.

According to the above configuration, at the scheduled hot water supply start time, the water heated to the boiling target temperature by the heat pump is stored in the tank. Therefore, in the hot water supply operation, it is possible to supply hot water at a desired hot water temperature without using another heating device.

The high-temperature anti-freezing temperature may be a temperature equal to or higher than the boiling target temperature.

The boiling-up target temperature is set to a temperature suitable for supplying water temperature-adjusted to the hot water supply temperature to the hot water supply location in the hot water supply operation. According to the above configuration, even if heat is released from the tank after the high-temperature anti-freezing operation is executed, the temperature of the water in the tank when the hot water supply operation is started is close to the boiling target temperature. Therefore, in the hot water supply operation at the scheduled hot water supply start time, it is possible to supply hot water at a desired hot water supply temperature. Therefore, the boiling-up operation, which is scheduled to be performed the second specific time before the scheduled hot water supply start time, is not required.

1 is a diagram schematically showing the configuration of a hot water supply system 2 according to an embodiment; FIG. FIG. 4 is a diagram showing an example of time zones during which hot water is supplied in a specific household; It is a figure which shows an example of the temperature table based on an Example, and a determination time table. 6 is a flowchart of anti-freezing operation processing according to the embodiment;

(Example)
As shown in FIG. 1 , the hot water supply system 2 according to this embodiment includes an HP (heat pump) unit 4 , a tank unit 6 and a burner unit 8 .

(Configuration of HP unit 4)
The HP unit 4 is a heat source that absorbs heat from outside air to heat water. The HP unit 4 comprises a heat pump heat source 17 consisting of a compressor 10 , a condenser 12 , an expansion valve 14 and an evaporator 16 . The HP unit 4 absorbs heat from outside air and heats water by circulating a refrigerant (for example, Freon-based refrigerant) through the compressor 10, the condenser 12, the expansion valve 14, and the evaporator 16 in this order. The compressor 10 pressurizes the refrigerant to high temperature and high pressure. The condenser 12 cools the refrigerant by heat exchange with water. An HP outgoing path 19 and an HP return path 21 are connected to both ends of the water flow path of the condenser 12, respectively. The expansion valve 14 reduces the pressure of the refrigerant to low temperature and low pressure. The evaporator 16 heats the refrigerant through heat exchange with the outside air. The HP unit 4 further includes a circulation pump 18 that circulates water through the condenser 12, a forward thermistor 20 that senses the temperature of the water flowing into the condenser 12, and a return thermistor 22 that senses the temperature of the water flowing out of the condenser 12. , an outside air temperature thermistor 23 that detects the outside air temperature TO, and an HP controller 24 that controls the operation of each component of the HP unit 4 .

(Configuration of tank unit 6)
The tank unit 6 has a tank 30 , a mixing valve 32 and a bypass control valve 34 . The tank 30 is a closed container whose outside is covered with a heat insulating material and which stores water inside. The capacity of the tank 30 of this embodiment is, for example, 100 liters. When the circulation pump 18 of the HP unit 4 is driven, the water at the bottom of the tank 30 is sent to the condenser 12 via the tank going path 31 and the HP going path 19 . The water heated to a high temperature by the condenser 12 is returned from the top of the tank 30 into the tank 30 via the HP return path 21 and the tank return path 33 . When the water heated by the HP unit 4 flows into the tank 30, a thermal stratification is formed inside the tank 30 in which a layer of hot water is stacked on a layer of cold water. The tank 30 is provided with an upper thermistor 36 for detecting the temperature of the upper water, an intermediate thermistor 37 for detecting the temperature of the intermediate water, and a lower thermistor 38 for detecting the temperature of the lower water. Hereinafter, the HP going route 19, the HP returning route 21, the tank going route 31, and the tank returning route 33 may be collectively referred to as a "circulation route".

Tap water is supplied to the tank unit 6 via a water supply path 40 . The water supply path 40 is provided with a pressure reducing valve 42 for reducing the pressure of the water supply and a water entry thermistor 44 for detecting the temperature of the water supply. The water supply path 40 branches into a tank water supply path 46 communicating with the bottom of the tank 30 and a tank bypass path 48 communicating with the mixing valve 32 . Check valves 50 and 52 are attached to the tank water supply path 46 and the tank bypass path 48, respectively. A water-side water quantity sensor 54 for detecting the flow rate of tap water flowing into the mixing valve 32 is attached to the tank bypass path 48 . The top of the tank 30 and the mixing valve 32 communicate with each other via a tank outlet path 56 . A check valve 58 and a hot water side water quantity sensor 60 for detecting the flow rate of water from the tank 30 flowing into the mixing valve 32 are attached to the tank hot water outlet path 56 .

The mixing valve 32 mixes the tap water flowing from the tank bypass path 48 and the water from the tank 30 flowing from the tank hot water outlet path 56 and sends the mixed water to the first hot water supply path 62 . The mixing valve 32 is driven by a stepping motor to adjust the opening on the tank bypass path 48 side (water side opening) and the opening on the tank hot water supply path 56 side (hot water side opening). A mixing thermistor 64 that detects the temperature of the water sent out from the mixing valve 32 is attached to the first hot water supply path 62 .

Hot water is supplied from the tank unit 6 to the hot water supply locations such as the kitchen, the shower, and the drain via the second hot water supply path 66 . A hot water supply outlet thermistor 68 for detecting the temperature of water supplied to the hot water supply location and a check valve 70 are attached to the second hot water supply path 66 . A hot water supply bypass path 72 communicates between the first hot water supply path 62 and the second hot water supply path 66 . A bypass control valve 34 is attached to the hot water supply bypass path 72 .

The tank unit 6 further comprises a tank controller 74 that controls the operation of each component of the tank unit 6 . Tank controller 74 includes non-volatile memory 76 . The nonvolatile memory 76 stores a temperature table 78a (see FIG. 3) and a determination time table 78b (see FIG. 3). Each table 78a, 78b will be described later in detail.

(Configuration of burner unit 8)
The burner unit 8 includes a burner 80 , a heat exchanger 82 , a bypass servo 84 , a water quantity servo 86 and a hot water filling valve 88 . The burner 80 is an auxiliary heat source device that heats water flowing through the heat exchanger 82 by combustion of fuel gas. Fuel gas is supplied to the burner 80 through a gas supply pipe (not shown). Water from the first hot water supply path 62 of the tank unit 6 flows into the heat exchanger 82 via the burner outward path 90 . The water that has passed through the heat exchanger 82 flows out to the second hot water supply path 66 of the tank unit 6 via the burner return path 92 . On the outward burner path 90, a water volume servo 86 for adjusting the flow rate of water flowing in the outward burner path 90 and a water volume sensor 91 for detecting the flow rate of water flowing in the outward burner path 90 are attached. The burner forward path 90 and the burner return path 92 are communicated via a burner bypass path 94 . A bypass servo 84 is attached to the connecting portion between the burner forward path 90 and the burner bypass path 94 . A bypass servo 84 adjusts the flow rate of water flowing from the burner forward path 90 to the burner bypass path 94 . A burner hot water supply thermistor 96 that detects the temperature of water flowing out of the heat exchanger 82 is attached to the burner return path 92 . A hot water filling path 98 branches off from the burner return path 92 . A hot water filling valve 88 is attached to the hot water filling path 98 . Hot water is supplied from the burner unit 8 to the hot water supply portion of the bathtub through a hot water supply path 98 .

The burner unit 8 further comprises a burner controller 100 and a remote controller 102 capable of communicating with the burner controller 100 . A burner controller 100 controls the operation of each component of the burner unit 8 . The remote controller 102 receives various operational inputs from the user via switches, buttons, and the like. In addition, remote control 102 notifies the user of various information regarding settings and operations of hot water supply system 2 by means of display and sound.

HP controller 24 and tank controller 74 can communicate with each other. Tank controller 74 and burner controller 100 can communicate with each other. Therefore, the HP controller 24, the tank controller 74, and the burner controller 100 cooperatively perform control, whereby the hot water supply system 2 can perform various operations such as boiling operation, hot water supply operation, and anti-freezing operation. Hereinafter, the HP controller 24, the tank controller 74, and the burner controller 100 are also collectively referred to simply as controllers.

The boiling-up operation, hot water supply operation, and anti-freezing operation performed by the hot water supply system 2 will be described below.

(boiling operation)
In the boiling operation, hot water supply system 2 drives HP unit 4 to heat water in tank 30 . When the boiling operation is started, the controller drives the compressor 10 of the heat pump heat source 17 to circulate the refrigerant in the order of the compressor 10, the condenser 12, the expansion valve 14, and the evaporator 16, and the circulation pump 18 to circulate water between the tank 30 and the condenser 12. As a result, the water sucked from the bottom of the tank 30 is heated to the boiling target temperature TA in the condenser 12 and returned to the top of the tank 30 . When all the water in the tank 30 is replaced with water heated to the boiling target temperature TA, the controller ends the boiling operation.

(hot water supply operation)
In the hot water supply operation, water at the hot water supply set temperature TS is supplied to the hot water supply location. The set hot water supply temperature TS is a temperature set by the user. When the sum of the flow rate detected by the cold water sensor 54 and the hot water sensor 60 (also called hot water supply flow rate) exceeds the minimum operating flow rate (for example, 2.4 L/min), the controller , it is determined that the hot water supply to the hot water supply point has started due to the opening of the faucet or the filling of the bathtub with hot water. The controller performs the following non-combustion hot water supply operation or combustion hot water supply operation according to the temperature detected by the upper thermistor 36 .

The controller executes the non-combustion hot water supply operation when the temperature detected by the upper thermistor 36 is equal to or higher than the hot water supply set temperature TS. In the non-combustion hot water supply operation, the controller prohibits the combustion operation of the burner 80 and adjusts the opening degree of the mixing valve 32 so that the temperature detected by the mixing thermistor 64 becomes the hot water supply set temperature TS. As a result, water whose temperature is adjusted to the hot water supply set temperature TS is supplied to the hot water supply location.

Further, when the temperature detected by the upper thermistor 36 is lower than the set hot water supply temperature TS, the controller executes combustion hot water supply operation. In the combustion hot water supply operation, the controller permits the combustion operation of the burner 80 so that the temperature detected by the mixing thermistor 64 is lower than the hot water supply set temperature TS by the minimum heating capacity of the burner 80. Adjust the opening of the mixing valve 32 . In this case, the high-temperature water supplied from the upper part of the tank 30 and the low-temperature water supplied from the water supply path 40 are mixed in the mixing valve 32 and then heated to the hot water supply set temperature TS by the burner 80 to supply hot water. supplied to the site. Note that the combustion hot water supply operation includes the case where the mixing valve 32 is fixed in the fully closed state on the tank 30 side. In this case, the controller adjusts the heating capacity of the burner 80 so that the water heated by the burner 80 reaches the hot water supply set temperature TS.

If the hot water supply flow rate falls below the minimum operating flow rate during the above non-combustion hot water supply operation or combustion hot water supply operation, the controller will indicate that hot water supply to the hot water supply location has ended due to closing of the faucet or completion of hot water filling to the bathtub. and terminates the hot water supply operation.

(Specification of scheduled hot water supply start time and boiling start time)
Next, determination of the scheduled hot water supply start time and the scheduled boiling start time will be described with reference to FIG. The scheduled hot water supply start time is a time used to specify the scheduled boiling start time and in the anti-freezing operation process (see FIG. 4), which will be described later. The scheduled hot water supply start time and the scheduled boiling start time are specified according to past hot water supply usage records. First, the controller identifies the scheduled hot water supply start time based on the hot water supply trend of a specific household. Specifically, every time hot water supply is performed in a specific household, the controller provides time information indicating the time when hot water supply started and the time when hot water supply ended, and supply time information indicating the amount of water supplied. store quantity information; The controller stores one day's worth of time information and supply amount information as one day's worth of driving history for a particular household. In this example, the controller stores the past 7 days of driving history for a particular household. Therefore, every 24 hours, the controller erases the driving history of eight days ago and stores the driving history of the previous day.

Next, the controller identifies the earliest time at which hot water supply was started for the first time in the past 7 days from the operation history of the specific household for the past 7 days. Hereinafter, this time is referred to as "first scheduled hot water supply start time S1". For example, the controller identifies 6:00 as the first scheduled hot water supply start time S1 (see FIG. 2) and stores it in the nonvolatile memory 76 . In addition, in the first hot water supply, water of about 5 L to 20 L is often supplied. In this case, the controller sets 30 liters as the target boiling water amount TW up to the first scheduled hot water supply start time S1.

In addition, the controller identifies the earliest time when the hot water filling operation was started in the past 7 days from the operation history of the specific household for the past 7 days. Hereinafter, this time is referred to as "second scheduled hot water supply start time B1". In this embodiment, a specific household is preset to start the hot water filling operation at 20:00 every day. For example, the controller identifies 20:00 as the second scheduled hot water supply start time B1 (see FIG. 2) and stores it in the nonvolatile memory 76 . In the hot water filling operation, water of about 150L to 180L is often supplied. In this case, the controller sets 100 liters as the target boiling water amount TW up to the second scheduled hot water supply start time B1.

Furthermore, the controller identifies the latest time when the last hot water supply ended in the past 7 days from the operation history of the specific household for the past 7 days. This time is hereinafter referred to as "hot water supply end time G1". For example, the controller identifies 0:00 as the hot water supply end time G1 (see FIG. 2).

Further, the controller specifies a first predetermined time period α, a second predetermined time period β, and a third predetermined time period γ based on the boiling target temperature TA and the boiling target water amount TW. The first predetermined time α is the time required for the boiling operation when heating the target boiling water amount of 30 liters to the target boiling temperature TA (for example, 45° C.). The second predetermined time β is the time required for the boiling operation when heating the target boiling water amount of 100 liters to the target boiling temperature TA (for example, 45° C.).

Next, as shown in FIG. 2, the controller identifies a first scheduled boiling-up start time S0, which is a time earlier than the first scheduled hot water supply start time S1 by the specified first predetermined time α, and A second scheduled boiling-up start time B0, which is the specified second predetermined time β before the second scheduled hot water supply start time B1, is specified. That is, the controller stores the first scheduled boiling start time S0 and the second scheduled boiling start time B0 in the nonvolatile memory 76 as scheduled boiling start times. Further, the controller specifies the heat pump stop time G0, which is the specified third predetermined time γ before the hot water supply end time G1. Then, when the scheduled boiling start time stored in the nonvolatile memory 76 arrives, the controller starts the boiling operation. Further, when the heat pump stop time G0 stored in the nonvolatile memory 76 arrives, the controller prohibits the boiling operation.

(Freezing prevention operation of HP unit 4)
When the outside air temperature is low, such as in winter, the water in the circulation paths (the HP going path 19, the HP returning path 21, the tank going path 31, and the tank returning path 33) may freeze. If water freezes, it may become impossible to perform boiling-up operation. Therefore, the hot water supply system 2 performs an anti-freezing operation to prevent the water in the circulation path from freezing.

(Anti-freezing operation processing)
The anti-freezing operation process executed by the controller will be described with reference to FIG. When the hot water supply system 2 is powered on, the process of FIG. 4 is started.

In step S10, the controller monitors that the circulating water temperature is below a first predetermined temperature (eg, "10°C"). The circulating water temperature is the water temperature detected by the forward thermistor 20 or the water temperature detected by the return thermistor 22, whichever is lower. When the circulating water temperature is lower than the first predetermined temperature, the controller determines YES in step S10, and the process proceeds to step S12.

In step S12, the controller determines whether or not the outside air temperature TO detected by the outside air temperature thermistor 23 is lower than a second predetermined temperature (eg, 5°C). When the outside air temperature TO is lower than the second predetermined temperature, the controller determines YES in step S12, and the process proceeds to step S20. On the other hand, when the outside air temperature TO is equal to or higher than the second predetermined temperature, the controller determines NO in step S12, and the process returns to step S10.

In step S20, the controller identifies the next scheduled hot water supply start time. The controller identifies the current time and identifies the time closest to the current time as the next scheduled hot water supply start time between the first scheduled hot water supply start time S1 and the second scheduled hot water supply start time B1. For example, when the current time, the first scheduled hot water supply start time S1, and the second scheduled hot water supply start time B1 are respectively "4:00", "6:00", and "20:00", the controller "6:00" is specified as the next scheduled hot water supply start time.

In step S22, the controller uses the set hot water supply temperature TS and the temperature table 78a (see FIG. 3) in the nonvolatile memory 76 to set the boiling temperature of the boiling operation to be executed before the next scheduled hot water supply start time. Identify the upper target temperature TA. As shown in FIG. 3, in the temperature table 78a, the set hot water supply temperature TS and the target boiling temperature TA are associated with each other. The boiling-up target temperature TA is set to a water temperature suitable for supplying water adjusted to the hot water supply set temperature TS to the hot water supply location in the hot water supply operation. For example, when the set hot water supply temperature TS is "38° C.", the controller specifies "45° C." as the boiling target temperature TA.

In step S24, the controller uses the outside air temperature TO detected by the outside air temperature thermistor 23, the boiling target temperature TA specified in step S22, and the determination time table 78b (see FIG. 3) in the nonvolatile memory 76. to specify the judgment time. The determination time is a time for determining which of low-temperature anti-freezing operation and high-temperature anti-freezing operation, which will be described later, is to be executed. The determination time table 78b is a table for specifying the determination time based on the outside air temperature TO and the target boiling temperature TA. As shown in FIG. 3, the lower the outside air temperature TO, the shorter the determination time, and the higher the boiling-up target temperature TA, the shorter the determination time. For example, the controller specifies "5.6 hours" as the determination time when the boiling-up target temperature TA and the outside air temperature TO are "45°C" and "0°C", respectively.

In step S30, the controller determines whether or not the subtraction time, which is the time obtained by subtracting the current time from the next scheduled hot water supply start time specified in step S20, is equal to or longer than the determination time specified in step S24. When the subtraction time is equal to or longer than the determination time, the controller determines YES in step S30, and the process proceeds to step S32. On the other hand, if the subtraction time is less than the determination time, the controller determines NO in step S30, and the process proceeds to step S40.

In step S32, the controller drives the heat pump heat source 17 and the circulation pump 18 to start the low-temperature anti-freezing operation. In the low-temperature anti-freezing operation, the controller controls the operation of the heat pump heat source 17 so that the temperature of the water in the circulation path reaches the low-temperature anti-freezing temperature (for example, 20° C.). In this embodiment, the low-temperature anti-freezing temperature is set to the minimum temperature required to prevent freezing of the water in the circulation path.

In step S34, the controller monitors whether the circulating water temperature becomes equal to or higher than the low-temperature anti-freezing temperature. When the circulating water temperature is equal to or higher than the low-temperature anti-freezing temperature, the controller determines YES in step S34, and the process proceeds to step S36.

In step S36, the controller changes the next boiling start scheduled time. First, the controller identifies the next boiling start scheduled time based on the current time. For example, when the current time, the first scheduled boiling start time S0, and the second scheduled boiling start time B0 are respectively "4:00", "5:45", and "19:30", the controller specifies "5:45" as the next boiling start scheduled time. Then, the controller shortens the predetermined time (the first predetermined time α or the second predetermined time β) corresponding to the specified next boiling start scheduled time by the delay time. In this embodiment, the controller specifies a new predetermined time that is the predetermined time shortened by 5 minutes. Then, the controller identifies a time that is a new predetermined time before the next scheduled boiling start time as the next scheduled boiling start time. In a modified example, the controller may specify the delay time based on the current temperature of the water in the tank 30 , the outside air temperature TO, and heat radiation from the tank 30 .

In step S<b>38 , the controller stops driving the heat pump heat source 17 and the circulation pump 18 . When the process of step S38 ends, the process of FIG. 4 ends.

When the controller determines NO in step S30, the controller drives the heat pump heat source 17 and the circulation pump 18 in step S40 to perform the high-temperature anti-freezing operation. In the high temperature antifreeze operation, the controller controls the operation of the heat pump heat source 17 so that the temperature of the water in the circulation path reaches the high temperature antifreeze temperature (for example, 45° C.). The hot antifreeze temperature is a temperature higher than the cold antifreeze temperature. Further, in this embodiment, the high-temperature anti-freezing temperature is the same temperature as the boiling-up target temperature TA. In the modified example, the high-temperature anti-freezing temperature may be different from the boiling-up target temperature TA as long as it is higher than the low-temperature anti-freezing temperature.

In step S42, the controller monitors whether the circulating water temperature becomes equal to or higher than the high temperature anti-freezing temperature. When the temperature of the circulating water is equal to or higher than the high-temperature anti-freezing temperature, the controller determines YES in step S42, and the process proceeds to step S44.

In step S44, the controller suspends the boiling operation to be performed before the next scheduled hot water supply start time specified in step S20. Therefore, even if the next scheduled boiling-up start time arrives, the controller does not perform the boiling-up operation. After step S44 ends, the process proceeds to step S38. When the process of step S38 ends, the process of FIG. 4 ends.

Heat is radiated from the tank 30 during the time from the end of the anti-freezing operation to the start of the next hot water supply operation (that is, the standby time). The longer the standby time is, the greater the heat radiation from the tank 30 is. Also, the higher the temperature of the water in the tank 30 is, the greater the heat radiation from the tank 30 is. According to the above configuration, the controller executes the low-temperature anti-freezing operation (YES in step S30 in FIG. 4) when the time from the start time of the anti-freezing operation to the scheduled hot water supply start time is equal to or longer than the determination time (YES in step S30 in FIG. 4). 4 step S32). If the time from the current time to the scheduled hot water supply start time is equal to or longer than the determination time, the waiting time is relatively long. In this case, most of the heat stored in the tank 30 during the low-temperature anti-freezing operation is dissipated during the standby time. The temperature of the water in the tank 30 after the low-temperature anti-freezing operation (ie, the low-temperature anti-freezing temperature) is lower than the temperature of the water in the tank 30 after the high-temperature anti-freezing operation (ie, the high-temperature anti-freezing temperature). Therefore, when the time from the current time to the next scheduled hot water supply start time is equal to or longer than the determination time, heat radiation from the tank 30 during the standby time can be suppressed as compared with the case where the high-temperature anti-freezing operation is executed. can.

Also, when the waiting time is short, the heat radiation from the tank 30 is small. According to the above configuration, the controller executes the high-temperature anti-freezing operation (step S40 ). Much of the heat stored in the tank 30 during the high temperature anti-freezing operation can be utilized in subsequent hot water supply operations. The temperature of the water in the tank 30 after the high-temperature anti-freezing operation (that is, the high-temperature anti-freezing temperature) is higher than the temperature of the water in the tank 30 after the low-temperature anti-freezing operation (that is, the low-temperature anti-freezing temperature). water at a temperature more suitable for Therefore, the anti-freezing operation is performed, and the heat stored in the tank 30 during the anti-freezing operation is also used as the heat used in the hot water supply operation to effectively utilize the water at the set hot water supply temperature TS. It can be done as quickly as possible (without using the burner unit 8).

Also, even if the standby time is the same, the lower the outside air temperature TO, the greater the heat radiation from the tank 30 . For this reason, in order to suppress the heat dissipation during the standby time when the outside air temperature TO is low to the same extent as the heat dissipation during the standby time when the outside air temperature TO is high, the standby time when the outside air temperature TO is low should be increased. It should be shorter than the waiting time in the case. As shown in FIG. 3, in the judgment time table 78b of the nonvolatile memory 76, the lower the outside air temperature TO, the shorter the judgment time. Therefore, it is possible to suppress the heat radiation from the tank 30 and effectively utilize the heat stored in the tank 30 during the anti-freezing operation, so that the water at the hot water supply set temperature TS can be discharged as quickly as possible. can.

Also, even if the standby time is the same, the higher the temperature of the water in the tank 30 is, the greater the heat radiation from the tank 30 is. Therefore, in order to suppress the heat dissipation during the standby time when the temperature of the water in the tank 30 is high to the same extent as the heat dissipation during the standby time when the temperature of the water in the tank 30 is low, the water in the tank 30 must be The standby time when the temperature is high must be shorter than the standby time when the temperature of the water in the tank 30 is low. As shown in FIG. 3, in the determination time table 78b of the non-volatile memory 76, the higher the boiling-up target temperature TA (that is, the high-temperature anti-freezing temperature), the shorter the determination time. Therefore, it is possible to suppress the heat radiation from the tank 30 and effectively utilize the heat stored in the tank 30 during the anti-freezing operation, so that the water at the hot water supply set temperature TS can be discharged as quickly as possible. can.

Further, as shown in FIG. 2, the controller can predict the scheduled hot water supply start times S1 and B1 based on the past hot water supply usage history, and the estimated hot water supply start time is set to the first predetermined time α or the second predetermined time. is configured to perform the boiling-up operation by the heat pump heat source 17 a predetermined time β before. According to such a configuration, the water heated to the boiling target temperature TA by the heat pump heat source 17 is stored in the tank 30 at the scheduled hot water supply start times S1 and B1. Therefore, in the hot water supply operation, even without using the burner unit 8, it is possible to supply hot water at the set hot water supply temperature TS.

As described above, the first predetermined time period α or the second predetermined time period β is set immediately before the scheduled hot water supply start times S1 and B1 when the low-temperature anti-freezing operation is not executed before the hot water supply operation. Set to end the run. When the low-temperature anti-freezing operation is executed, part of the heat stored in the tank 30 during the low-temperature anti-freezing operation remains in the tank 30 at the start of the subsequent boiling-up operation. That is, the temperature of the water in the tank 30 after the low temperature antifreeze operation is executed is higher than the temperature of the water in the tank 30 when the low temperature antifreeze operation is not executed. Therefore, in a situation after the low-temperature anti-freezing operation has been executed, if the boiling-up operation is started before the scheduled hot water supply start time S1 or B1 by the first predetermined time α or the second predetermined time β, The boiling operation ends before the scheduled start times S1 and B1. In this case, heat is radiated from the tank 30 from the end of the boiling operation to the start of the hot water supply operation. According to the above configuration, the controller shortens the first predetermined time period α or the second predetermined time period β when the low-temperature anti-freezing operation is executed. In this case, the time from the end of the boiling operation to the scheduled hot water supply start times S1 and B1 can be shortened. Therefore, heat radiation from the tank 30 can be suppressed.

Also, the high temperature anti-freezing temperature is the same as the boiling target temperature TA. The boiling-up target temperature TA is set to a water temperature suitable for supplying water adjusted to the hot water supply set temperature TS to the hot water supply location in the hot water supply operation. Therefore, even if heat is released from the tank 30 after the high-temperature anti-freezing operation is executed, the temperature of the water in the tank 30 when the hot water supply operation is started is close to the boiling target temperature TA. Therefore, in the hot water supply operation at the next scheduled hot water supply start time S1, B1, it is possible to supply water at the hot water supply set temperature TS. Therefore, the boiling-up operation, which is scheduled to be performed at predetermined times α and β before the next scheduled hot water supply start times S1 and B1, becomes unnecessary.

(correspondence relationship)
The tank hot water path 56 is an example of the "hot water path". A controller is an example of a "controller." The outside temperature thermistor 23 is an example of an "outside temperature sensor." The current time is an example of the "anti-freezing start time." The determination time is an example of the "first specific time". The first predetermined time α and the second predetermined time β are examples of the “second specific time”.

Although each embodiment has been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(First Modification) The determination time may be the same regardless of the outside air temperature TO and the boiling-up target temperature TA. In another modification, the determination time is shorter as the outside air temperature TO is lower, but may be the same regardless of the boiling-up target temperature TA. In another modification, the determination time is shorter as the boiling-up target temperature TA is higher, but may be the same regardless of the outside air temperature TO.

(Second Modification) The controller does not need to specify the scheduled hot water supply start time and the scheduled boiling start time according to past hot water supply usage records. In this modification, in step S20 of FIG. 4, the controller identifies the scheduled hot water supply start time reserved by the user as the next scheduled hot water supply start time. Further, in this modification, the controller executes the low-temperature anti-freezing operation when the scheduled hot water supply start time has not been reserved by the user.

(Third Modification) In FIG. 4, the process of step S36 can be omitted.

(Fourth Modification) The hot water supply system 2 may not include the burner unit 8 .

The technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. In addition, the techniques exemplified in this specification or drawings can simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

2: Hot water supply system 4: HP unit 6: Tank unit 8: Burner unit 10: Compressor 12: Condenser 14: Expansion valve 16: Evaporator 17: Heat pump heat source 18: Circulation pump 19: HP forward path 20: Forward thermistor 21 : HP return path 22 : Return thermistor 23 : Outside air temperature thermistor 24 : HP controller 30 : Tank 31 : Tank going path 32 : Mixing valve 33 : Tank return path 34 : Bypass control valve 36 : Upper thermistor 37 : Intermediate thermistor 38 : Lower thermistor 40 : Water supply path 42 : Pressure reducing valve 44 : Water inflow thermistor 46 : Tank water supply path 48 : Tank bypass path 50 : Check valve 52 : Check valve 54 : Water-side water quantity sensor 56 : Tank hot water supply path 58 : Check valve 60 : hot water side water quantity sensor 62 : first hot water supply path 64 : mixed thermistor 66 : second hot water supply path 68 : hot water supply outlet thermistor 70 : check valve 71 : water supply path 72 : hot water supply bypass path 74 : tank controller 76 : nonvolatile memory 78a : Temperature table 78b : Judgment time table 80 : Burner 82 : Heat exchanger 84 : Bypass servo 86 : Water volume servo 88 : Hot water filling valve 90 : Burner outward path 91 : Water volume sensor 92 : Burner return path 94 : Burner bypass path 96 : Burner Hot water supply thermistor 98: Hot water supply path 100: Burner controller 102: Remote controller

Claims (5)

a heat pump heat source for heating water;
a tank for storing water heated by the heat pump heat source;
a circulation path connecting the heat pump heat source and the tank;
a circulation pump provided in the circulation path;
a hot water outlet connected to the tank for supplying water stored in the tank to a hot water supply location;
a controller;
The control device is
a hot water supply operation for supplying the water stored in the tank to the hot water supply location;
A boiling-up operation in which the circulation pump and the heat pump heat source are driven and water heated to a boiling-up target temperature is stored in the tank;
anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent the water in the circulation path from freezing,
The control device is
Capable of acquiring a scheduled hot water supply start time, which is the time at which the next hot water supply operation is scheduled to start,
The control device, in the anti-freezing operation,
When the time from the antifreeze start time, which is the time to start the antifreeze operation, to the scheduled hot water supply start time is equal to or longer than a first specific time, the circulation pump and the heat pump heat source are driven, and Execute low-temperature anti-freezing operation to heat the water of the
When the time from the antifreeze start time to the scheduled hot water supply start time is less than the first specific time, the circulation pump and the heat pump heat source are driven to reduce the water in the circulation path to the low temperature antifreeze temperature. Execute high temperature anti-freezing operation to heat to a high temperature anti-freezing temperature higher than
The high-temperature anti-freezing temperature is the boiling target temperature,
The control device is configured to perform the boiling operation a second specific time before the scheduled hot water supply start time,
The water heater , wherein the second specific time is a time different from the first specific time and is a time required for the boiling operation . is a water heater,
a heat pump heat source for heating water;
a tank for storing water heated by the heat pump heat source;
a circulation path connecting the heat pump heat source and the tank;
a circulation pump provided in the circulation path;
a hot water outlet connected to the tank for supplying water stored in the tank to a hot water supply location;
a controller;
The control device is
a hot water supply operation for supplying the water stored in the tank to the hot water supply location;
A boiling-up operation in which the circulation pump and the heat pump heat source are driven and water heated to a boiling-up target temperature is stored in the tank;
anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent the water in the circulation path from freezing,
The control device is
Capable of acquiring a scheduled hot water supply start time, which is the time at which the next hot water supply operation is scheduled to start,
The control device, in the anti-freezing operation,
When the time from the antifreeze start time, which is the time to start the antifreeze operation, to the scheduled hot water supply start time is equal to or longer than a first specific time, the circulation pump and the heat pump heat source are driven, and Execute low-temperature anti-freezing operation to heat the water of the
When the time from the antifreeze start time to the scheduled hot water supply start time is less than the first specific time, the circulation pump and the heat pump heat source are driven to reduce the water in the circulation path to the low temperature antifreeze temperature. Execute high temperature anti-freezing operation to heat to a high temperature anti-freezing temperature higher than
The water heater further comprises an outside air temperature sensor that detects the outside air temperature,
The water heater, wherein the lower the outside air temperature, the shorter the first specific time. a heat pump heat source for heating water;
a tank for storing water heated by the heat pump heat source;
a circulation path connecting the heat pump heat source and the tank;
a circulation pump provided in the circulation path;
a hot water outlet connected to the tank for supplying water stored in the tank to a hot water supply location;
a controller;
The control device is
a hot water supply operation for supplying the water stored in the tank to the hot water supply location;
A boiling-up operation in which the circulation pump and the heat pump heat source are driven and water heated to a boiling-up target temperature is stored in the tank;
anti-freezing operation for driving the circulation pump and the heat pump heat source in order to prevent the water in the circulation path from freezing,
The control device is
Capable of acquiring a scheduled hot water supply start time, which is the time at which the next hot water supply operation is scheduled to start,
The control device, in the anti-freezing operation,
When the time from the antifreeze start time, which is the time to start the antifreeze operation, to the scheduled hot water supply start time is equal to or longer than a first specific time, the circulation pump and the heat pump heat source are driven, and Execute low-temperature anti-freezing operation to heat the water of the
When the time from the antifreeze start time to the scheduled hot water supply start time is less than the first specific time, the circulation pump and the heat pump heat source are driven to reduce the water in the circulation path to the low temperature antifreeze temperature. Execute high temperature anti-freezing operation to heat to a high temperature anti-freezing temperature higher than
The water heater , wherein the higher the anti-freezing temperature, the shorter the first specific time. The water heater according to claim 2 or 3 , wherein the high-temperature anti-freezing temperature is a temperature equal to or higher than the boiling target temperature. The control device is
The scheduled hot water supply start time can be obtained based on a history of past hot water supply to the hot water supply location,
The water heater according to any one of claims 1 to 4 , wherein the boiling operation is performed a second specific time before the scheduled hot water supply start time.

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